Multimodal Audio Decoder Error Concealment

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Solution Overview

Problem

Existing adaptive distribution formats for audiovisual media struggle with bandwidth efficiency, computational efficiency, error resilience, and seamless bitrate switching, particularly in environments with transient bitrate limitations, leading to noticeable disruptions in media streaming.

Innovation Solution

A multimodal decoding system that adapts between parametric, discrete, and keep modes to reconstruct n-channel audio signals by selecting the appropriate mode based on the current and previous frames' coding regimes, using a controller to manage mode transitions and error handling, ensuring continuous audio output even with defective frames.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If adaptive distribution format switches between higher-bitrate and lower-bitrate modes, then bandwidth efficiency is improved, but error resilience deteriorates due to increased vulnerability to data losses during streaming

Engineering Contradiction:
Improvebandwidth efficiencyVSAvoiderror resilience
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The system dynamically switches between higher-bitrate and lower-bitrate modes based on network conditions, making the distribution format adaptable rather than static. This dynamic adaptation allows the system to optimize bandwidth efficiency while maintaining error resilience through appropriate mode selection and transition management.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements preparatory measures for error handling by introducing redundancy mechanisms and error concealment strategies before data losses occur. This includes using robust coding schemes and maintaining buffer states that can compensate for potential packet losses, thereby cushioning the impact of errors during streaming.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Quantity of substance

If adaptive distribution format is implemented, then bandwidth efficiency is improved, but device complexity increases due to multiple coding modes and transition management

Engineering Contradiction:
Improvebandwidth efficiencyVSAvoidcoding system complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent designs a universal coding framework that can operate in multiple modes (higher-bitrate and lower-bitrate) within a single system architecture. This multi-functional approach allows the same decoding system to handle different bitrate conditions without requiring separate dedicated systems, thereby managing complexity while maintaining bandwidth efficiency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system manages complexity by changing operational parameters (bitrate mode, coding scheme) rather than restructuring the entire system architecture. This allows adaptive distribution to be achieved through parameter adjustment and mode switching within an existing framework, reducing the need for complex additional components.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If seamless bitrate switching is implemented, then adaptability to network conditions is improved, but noticeable disruptions occur during mode transitions

Engineering Contradiction:
Improvebitrate adaptationVSAvoidperceptible disruptions
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent prepares for mode transitions in advance by pre-processing data and maintaining buffer states that facilitate smooth switching. This preliminary preparation ensures that when bitrate mode changes occur, the transition is seamless and imperceptible to the end user, maintaining adaptability while eliminating disruptions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system maintains continuous audio output and decoding operations during mode transitions, ensuring that the useful action of audio playback never interruptions. This continuity is achieved through careful buffer management and cross-fading techniques that bridge the transition between different bitrate modes without creating perceptible gaps or disruptions.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP2862166B1Error concealment strategy in a decoding system
Publication Date: 2018.03.07 DOLBY INTERNATIONAL AB
  • EP2862166B1 patent drawingFigure 1
  • EP2862166B1 patent drawingFigure 2~3
  • EP2862166B1 patent drawingFigure 4~5

AI summary

A decoding system reconstructs an audio signal based on an input signal representing the audio signal by parametric coding or by n discretely coded channels. Parametric decoding proceeds on the basis of a core signal and mixing parameters controlling a spatial synthesis stage, which is supplied with a downmix signal. A controller is responsible for controlling the components of the decoding system, whether in steady-state parametric mode, steady-state discrete decoding mode and transitions between these. In defective frames of the input signal, which do not allow the mixing parameters to be decoded, the controller is configured to perform various error handling procedures including: parametric decoding using previous values of the mixing parameters; continuing parametric decoding for a limited duration, and/or outputting the core signal without spatial synthesis.